Collapsible/expandable prosthetic heart valves with native calcified leaflet retention features

ABSTRACT

A prosthetic heart valve includes an annular frame that is adapted for (1) delivery into a patient&#39;s native heart valve annulus in a circumferentially collapsed condition, and (2) circumferential re-expansion when in the annulus, the frame, in an expanded condition. The frame having a longitudinal axis, an inflow end and an outflow end, a first portion of the frame adjacent the inflow end inclining radially outwardly in a direction toward the inflow end, and a second portion of the frame between the first portion and the outflow end bulging radially outwardly, the second portion of the frame being positioned between a first axial distance from the inflow end and a second axial distance from the inflow end. The frame also includes a plurality of commissure members. The heart valve further includes a flexible leaflet structure disposed in the frame.

This application is a continuation application of U.S. application Ser.No. 14/824,209, filed Aug. 12, 2015, which is a continuation applicationof U.S. application Ser. No. 14/280,868, filed May 19, 2014 which is acontinuation application of U.S. application Ser. No. 12/733,763, filedMar. 18, 2010, which is a national phase entry under 35 U.S.C. §371 ofInternational Application No. PCT/US2008/11181, filed Sep. 26, 2008,published in English, which claims the benefit of U.S. ProvisionalPatent Application No. 60/995,845, filed Sep. 28, 2007, the disclosuresof all of which are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates to collapsible/expandable prosthetic heart valves(especially prosthetic aortic valves) for use with non-resectedcalcified native valves. The prosthetic heart valve design incorporatesfeatures that hold open the native calcified leaflets away from the newvalve.

BRIEF SUMMARY OF THE INVENTION

In accordance with certain possible aspects of the invention, aprosthetic heart valve may utilize expansion of fork-like fingers topush calcified native leaflets out of the way. This eliminatesinterference with the newly deployed prosthetic valve and maximizeshemodynamic performance. It also enhances prosthetic valve frameanchoring in the patient as a result of the fingers engaging thecalcified leaflets.

A prosthetic heart valve in accordance with the invention may becircumferentially collapsible and re-expandable, and may include anannular frame structure and a flexible leaflet structure disposed in theframe structure. The frame structure is preferably adapted for deliveryinto a patient's native heart valve annulus in a circumferentiallycollapsed condition. The frame structure is preferably further adaptedfor circumferential re-expansion when in the above-mentioned annulus.The frame structure preferably includes a leaflet restraining structurefor pushing radially outwardly on a patient's native heart valve leaflet(or leaflets) when the frame structure is re-expanded. The leafletrestraining structure is preferably cantilevered from an annulus portionof the frame structure. (The annulus portion is the portion of the framestructure that re-expands in the native valve annulus.) Moreparticularly, the leaflet restraining structure is preferablycantilevered from the annulus portion to a free end of the leafletrestraining structure that is downstream from the annulus portion in thedirection of blood flow through the prosthetic valve when the prostheticvalve is in use in the patient.

The above-mentioned leaflet restraining structure may be resilientlybiased to incline radially outwardly from the annulus portion as oneproceeds along the restraining structure from the annulus portion towardthe free end of the restraining structure.

The leaflet restraining structure may include a plurality of fingersthat are spaced from one another in a direction that is circumferentialaround the annulus portion. Each of these fingers may be cantileveredfrom the annulus portion and may extend from the annulus portion in thedirection of blood flow through the implanted prosthetic valve.

Each of the above-mentioned fingers may have a free end that is remotefrom the annulus portion. All of the fingers may extend to approximatelythe same distance downstream from the annulus portion in the directionof blood flow. Alternatively, a first of the fingers may extend agreater distance downstream from the annulus portion in the direction ofblood flow than a second of the fingers.

The annulus portion may include two (or more) circumferentially spacedcommissure regions. In such a case, and in the case of the alternativementioned in the immediately preceding paragraph, the fingers may alsobe circumferentially spaced from one another between two of thecommissure regions, and the above-mentioned first finger may becircumferentially closer to one of the above-mentioned two commissureregions than the above-mentioned second finger is to either of those twocommissure regions.

In a case in which the leaflet restraining structure includes aplurality of fingers, the leaflet restraining structure may furtherinclude a linking structure between two circumferentially adjacent onesof the fingers. This linking structure may be downstream from theannulus portion in the direction of blood flow through the implantedprosthetic valve.

The immediately above-mentioned linking structure may be collapsible andre-expandable in a direction that is circumferential around the annulusportion.

The location of the above-mentioned linking structure may be at the endsof the linked fingers that are remote from the annulus portion.

The annulus portion may include a plurality of circumferentially spacedcommissure regions, and the leaflet restraining structure may becircumferentially spaced between two circumferentially adjacent ones ofthose commissure regions. Especially in such a case, the leafletrestraining structure may be one of a plurality of similar leafletrestraining structures. Each of these leaflet restraining structures maybe circumferentially spaced between a respective one of a plurality ofpairs of circumferentially adjacent ones of the commissure regions.

The prosthetic heart valve may be an aortic valve, which may furthercomprise a further frame structure that includes an annular aorticportion and a plurality of struts or links between the aortic portionand the annulus portion. The aortic portion may be adapted for deliveryinto a patient's aorta in a circumferentially collapsed condition. Theaortic portion may be further adapted to circumferentially re-expandwhen in the aorta. The aortic portion is preferably downstream from thefree end of the leaflet restraining structure in the direction of bloodflow. The above-mentioned struts or links are preferablycircumferentially spaced from the leaflet restraining structure.

In cases like those mentioned in the immediately preceding paragraph,the annulus portion may include a plurality of circumferentially spacedcommissure regions. The above-mentioned struts or links may then connectto the annulus portion adjacent the commissure regions. For example, theleaflet restraining structure may be circumferentially spaced betweenfirst and second circumferentially adjacent ones of the links, and thefirst and second links may be respectively connected to the annulusportion adjacent respective first and second circumferentially adjacentones of the commissure regions.

Further features of the invention, its nature and various advantages,will be more apparent from the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a simplified isometric or perspective view of an illustrativeembodiment of a prosthetic heart valve in accordance with the invention.

FIG. 1b shows the FIG. 1a structure from another angle.

FIG. 1c shows the FIG. 1b structure from yet another angle.

FIG. 1d shows the FIG. 1c structure from still another angle.

FIG. 2a is a view similar to FIG. 1a for another illustrative embodimentof a prosthetic heart valve in accordance with the invention.

FIG. 2b shows the FIG. 2a structure from another angle.

FIG. 2c is similar to FIG. 2b , but FIG. 2c shows only some of thestructure that is shown in FIG. 2 b.

FIG. 2d shows the FIG. 2c structure from another angle.

FIG. 3a is a simplified view of an illustrative embodiment of aprosthetic heart valve component in accordance with the invention. FIG.3a shows the depicted component as though cut along a vertical axis andthen laid out flat.

FIG. 3b is similar to FIG. 3a for another illustrative embodiment of theinvention.

FIG. 3c is similar to FIG. 3b for yet another illustrative embodiment ofthe invention.

FIG. 3d is similar to FIG. 3c for still another illustrative embodimentof the invention.

DETAILED DESCRIPTION

A collapsible and re-expandable prosthetic aortic valve that canself-anchor around the native commissures in the valsalva sinus is shownin Alkhatib PCT patent application No. PCT/US08/09950, filed Aug. 21,2008, which is hereby incorporated by reference herein in its entirety.The illustrations that form part of the present disclosure areembodiments of valves like those shown in the above-mentioned reference,with the addition of leaflet retention or restraining features inaccordance with this invention. It will be understood that theparticular structures shown and described herein are only illustrative,and that the invention can be applied to many other prosthetic valveconstructions. Some of these possible variations will be mentioned laterin this specification.

FIGS. 1a-d are several views of an illustrative embodiment of theinvention, including fork-like fingers 10 for pushing a patient's nativeleaflet tissue (which may be calcified) out of the way of the leafletstructure 20 of prosthetic heart valve 30. The upper free ends offingers 10 are cantilevered from annular stent structure 40 of thevalve. When the valve is implanted in a patient, stent structure 40resides in or near the patient's native valve annulus. Hence thisportion 40 of the frame structure of valve 30 may sometimes be referredto as the annulus portion of the frame structure. Valve 30 is configuredfor use as an aortic valve replacement. In such use, an annular aorticportion 50 of the valve resides in the patient's aorta downstream (inthe direction of blood flow through the implanted valve) from thepatient's native valve annulus. Portions 40 and 50 are connected to oneanother by a plurality of links or struts 60 that pass through thepatient's native valsalva sinus and that bulge out into the outwardlybulging lobes of the valsalva sinus. Other details of the constructionof valve 30 will more apparent from the above-mentioned Alkhatibreference.

Note that all of the valves shown herein may be elastically collapsiblein the annular or circumferential direction to a reduced annular orcircumferential size that is suitable for delivery into a patient in aless invasive way (e.g., through tube-like delivery apparatus such as acatheter, a trocar, a laparoscopic instrument, or the like). When thevalve reaches the intended site for implantation, the valve mayelastically re-expand to normal operating size (e.g., the size shown inFIGS. 1a-d ). In all cases herein, the valve frame structure like10/40/50/60 may be made of a highly elastic metal such as nitinol, whileleaflet structure 20 may be made of a synthetic material such aspolymer, a natural material such as tissue, or another suitable flexiblematerial. In addition to the structural elements shown herein, valves inaccordance with this invention may also include other elements such asother layers of tissue and/or fabric (e.g., an outer fabric cover).

FIGS. 2a-d are several views of another illustrative embodiment of theinvention. Reference numbers are repeated from FIGS. 1a-d for featuresin FIGS. 2a-d that are similar to features in FIGS. 1a-d . FIGS. 2c andd omit depiction of the actual leaflet structure 20 to better revealcertain other features. The principal difference from FIGS. 1a-d is theinclusion in FIGS. 2a-d of collapsible/expandable interconnections 12between the upper (cantilevered) ends of certain ones of fork-likefingers 10.

FIGS. 3a-d show several further alternative embodiments of the metalframe structure 10/40/50/60/etc. of valves in accordance with theinvention. Again, reference numbers are repeated from earlier FIGS. forgenerally similar components. FIGS. 3a-d show each metal frame structureas though it has been cut along a longitudinal (vertical) axis and thenlaid out flat. In addition, FIGS. 3a-d show each metal structure in theapproximate condition (especially from left to right as viewed in theseFIGS.) that it has when annularly collapsed for delivery into a patientin reduced annular or circumferential size. Thus the serpentine orcellular structures (e.g., 40, 50, 12) that extend in the annulardirection around the valve are somewhat collapsed or compressed in theleft-right direction as viewed in FIGS. 3 a-d. Annular portions 40 and50 shown in FIGS. 3a-d are of a closed-cell design. This is analternative embodiment to the undulating strut design shown in theearlier FIGS. (Again, it is emphasized that the structures shown inFIGS. 3a-d are not actually flat at any time during their use. They arealways closed, annular structures. The flat depictions shown in FIGS.3a-d are only employed for convenience herein.)

In FIG. 3a the upper ends of cantilevered fork-like fingers 10 are free(e.g., as in FIGS. 1a-d ), but these fingers differ in length. Inparticular, fingers 10 are longer near (in the circumferentialdirection) each of the three circumferentially spaced commissure posts42 of the valve, and shorter where farther (in the circumferentialdirection) from the commissure posts. Another way to state this is bysaying that the fingers 10 that are circumferentially closer tocommissure posts 42 extend farther in the distal or downstream directionthan the fingers 10 that are circumferentially farther from thecommissure posts. FIG. 3b shows fingers 10 all of the same length andwith their upper ends free.

FIG. 3c shows an embodiment like FIG. 3a , but with the upper ends ofthe fingers 10 of different lengths linked by serpentine structures 12.Note that each serpentine structure 12 links only the fingers 10 in aset of such fingers that are located between two circumferentiallyadjacent ones of commissure posts 42. Thus the fingers 10 in such a setand the serpentine structure 12 linking those fingers collectivelycomprise a leaflet restraining structure that is cantilevered upwardlyfrom annulus portion 40 of the prosthetic valve frame. This structure asa whole (i.e., the set of fingers 10 and the link 12) has a free end(i.e., its upper end, which in this case is defined by link 12).

FIG. 3d shows an embodiment like FIG. 3b , but with the upper ends ofequal-length fingers 10 linked by serpentine structures 12. Once again,in FIG. 3d , each set of fingers 10 (between two circumferentiallyadjacent commissure posts) and the associated link 12 collectivelyconstitute a leaflet restraining structure that is cantilevered up fromannulus portion 40 to a free end (i.e., link 12). In embodiments withoutlinks 12, the fingers 10 themselves constitute the leaflet restrainingstructure of this invention.

Recapitulating and extending the above, the following are some of theimportant aspects of the invention.

Features 10 (possibly with links 12) are incorporated onto a collapsiblevalve frame and are designed specifically to hold the native calcifiedleaflet back (e.g., radially outwardly) and away from the replacementvalve.

Features 10 (possibly with links 12) are preferably not tall enough suchthat they would obstruct the coronary artery ostia.

The cantilevered leaflet retention feature typically includes severalelongated, curved, fork-like fingers 10 that can be free-standing orinterconnected (e.g., as shown at 12) at the distal (downstream) end.

The fingers 10 are connected to the main stent frame at their proximal(upstream) end.

The fork-like fingers 10 may be curved radially outward, away from thereplacement valve.

The fork-like fingers 10 (possibly with links 12) have adequatestiffness in the radial direction to hold the calcified native valve inan open (radially outward) position.

The fork-like fingers 10 (possibly with links 12) can be scalloped(e.g., FIG. 3a or 3 c) or straight (e.g., FIG. 3b or 3 d) at theirdistal end.

The fork-like fingers 10 (possibly with links 12) enhance anchoring ofthe prosthetic valve as a result of engaging the calcified leaflets.

While curved (radially) outward fork-like members 10 will do a good jobkeeping calcified leaflets out of the way, alternate designs can also beused, ranging from straight up fingers 10 to straight fingers inclinedat an angle so that they are radially farther out at their free endsthan where joined to annulus portion 40. Preferably, the prostheticvalve frame's geometry is designed to oppose the native leaflet onceimplanted and is capable of holding open, pushing outwards, engaging,and displacing the native leaflets in desired patterns to clearcoronaries, and anchoring in the native leaflets. Many suitablegeometries are capable of achieving these goals. The geometries can varysignificantly and only some of the possible geometries are describedherein.

Although the presently preferred stent structures (like 10/40/50/60) areself-expanding (i.e., elastically deformed), the present invention isequally applicable to balloon-expandable (i.e., plastically deformed)stents or a combination of self-expanding and balloon expandable (e.g.,where arms like 10 are resiliently self-expanding, but the rest of thecage like 40/50/60 may be balloon-expanded). The balloon-expandablestents, which can be made of stainless steel, can be used withspecifically designed balloons that have, for example, a bulbousmidsection. The balloon-expendable stents can also be enlarged in two ormore steps. A straight conventional balloon can be used first to anchorone or more stent structures of the valves. A second spherical ballooncan then be used to specifically expand the other structure orstructures such as fingers 10.

The structures like fingers 10 of this invention can also be designed toprovide the following benefits. These structures preferably move thenative calcified leaflets radially outwardly away from the new valvestructure to avoid potential abrasion of the new valve tissue 20 againstthe calcified, diseased tissue. Use of this invention can provide morespace for a bigger prosthetic valve and better hemodynamics. Thestructures like 10/12 of this invention can deform the diseased leafletsin such a way as to avoid potential coronary blockage (i.e. occlusion ofthe ostium of a coronary artery). The structures like 10/12 can bedesigned to also help with stability and anchoring of the prostheticvalve in the patient. Prior known collapsible prosthetic valves mayinclude cages that are intended to push diseased leaflets out of theway. But these previously known structures do not attempt to control orpreferentially displace the diseased leaflets in a specificconfiguration to provide the benefits described above for the presentinvention.

The attachment point of fingers 10 to the stent is described as beingpreferably at or near the proximal end of the prosthetic valve framestructure using the proximal end of the fingers. In another embodimentof the invention, the fingers can extend down from the distal end ofstent (outflow side). Other combinations of attachment are also possible(e.g., stent inflow side and members 60 or stent outflow side andmembers 60).

The foregoing features can be incorporated on minimally invasivesurgically implanted valves where resection of the native calcifiedleaflets has not been performed or is not possible.

An advantage of providing leaflet restraining structures 10/12 asstructures that are cantilevered from other structure of the valve frameis that this facilitates giving the leaflet restraining structuresvarious properties that can be relatively independent of the propertiesof other parts of the frame. For example, the extent to which leafletrestraining structures 10/12 incline or extend radially outwardly can bemade to depend solely (or at least largely) on the design of thosestructures per se, and can be independent of the shape, location, etc.,of other adjacent frame components such as links 60, commissure posts42, aortic portion 50, etc. Similarly, those other portions of the valvecan be designed to have properties that are independent of theproperties of leaflet restraining structures 10/12. Examples ofproperties that can thus be designed independently for structures 10/12,on the one hand, and other portions of the frame, on the other hand,include (1) collapsed location (i.e., location during delivery), (2)re-expanded location (i.e., location when deployed and implanted in thepatient), (3) size, (4) shape, (5) stiffness, (6) strength, (7)resilience, etc.

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention. For example, the number of leaflet restrainingstructures that are provided can be more or less than the number shownherein.

1. (canceled)
 2. A prosthetic heart valve comprising: an annular framethat is adapted for (1) delivery into a patient's native heart valveannulus in a circumferentially collapsed condition, and (2)circumferential re-expansion when in the annulus, the frame including aplurality of struts forming cells, a plurality of first closed cellshaving a first size circumferentially arranged in at least one row, anda plurality of second closed cells having a second size smaller than thefirst size, each of the plurality of second closed cells being nestedwithin a corresponding one of the plurality of first closed cells andincluding an attached end coupled to the corresponding one of theplurality of first closed cells, and a free end, the frame furtherincluding a plurality of commissure features; and a valve assemblyincluding a plurality of leaflets and a cover.
 3. The prosthetic valveof claim 2, wherein the frame includes an inflow end and an outflow end,each attached end of the plurality of second closed cells being coupledto the corresponding one of the plurality of first closed cells adjacentthe inflow end.
 4. The prosthetic valve of claim 2, wherein theplurality of second closed cells are nested within a single row of theplurality of first closed cells.
 5. The prosthetic valve of claim 2,wherein the plurality of second closed cells include groups of secondclosed cells equally spaced around the circumference of the frame. 6.The prosthetic valve of claim 5, wherein each group of second closedcells includes a single second closed cell.
 7. The prosthetic valve ofclaim 5, wherein each group of second closed cells includes a pair ofsecond closed cells.
 8. The prosthetic valve of claim 2, each of theplurality of second closed cells shares at least one strut with one ofthe plurality of first closed cells.
 9. The prosthetic valve of claim 2,wherein the plurality of leaflets includes three leaflets.
 10. Theprosthetic valve of claim 2, wherein the plurality of leaflets areformed from a biological tissue.
 11. The prosthetic valve of claim 2,wherein the cover includes an outer fabric cover.
 12. The prostheticvalve of claim 2, wherein the plurality of leaflets are coupled to theframe at the plurality of commissure features.
 13. A prosthetic heartvalve comprising: an annular frame that is adapted for delivery into apatient's native heart valve annulus in a circumferentially collapsedcondition, and circumferential re-expansion when in the annulus, theframe including a plurality of struts forming cells, a plurality offirst closed cells having a first size circumferentially arranged in atleast one row, and a plurality of second closed cells having a secondsize smaller than the first size, each of the plurality of second closedcells being nested within a corresponding one of the plurality of firstclosed cells and coupled to the corresponding one of the plurality offirst closed cells at two attachment points, the frame further includinga plurality of commissure features; and a valve assembly including aplurality of leaflets and a cover.
 14. The prosthetic valve of claim 13,wherein the frame includes an inflow end and an outflow end, eachattached end of the plurality of second closed cells being coupled tothe corresponding one of the plurality of first closed cells adjacentthe inflow end.
 15. The prosthetic valve of claim 13, wherein theplurality of second closed cells are nested within a single row of theplurality of first closed cells.
 16. The prosthetic valve of claim 13,wherein the plurality of second closed cells include groups of secondclosed cells equally-spaced around the circumference of the frame. 17.The prosthetic valve of claim 16, wherein each group of second closedcells includes a single second closed cell.
 18. The prosthetic valve ofclaim 16, wherein each group of second closed cells includes a pair ofsecond closed cells.
 19. The prosthetic valve of claim 13, each of theplurality of second closed cells shares at least one strut with one ofthe plurality of first closed cells.
 20. A prosthetic heart valvecomprising: an annular frame that is adapted for delivery into apatient's native heart valve annulus in a circumferentially collapsedcondition, and circumferential re-expansion when in the annulus, theframe including a plurality of struts forming cells, a plurality offirst closed cells having a first size circumferentially arranged in atleast one row, and a plurality of second closed cells having a secondsize smaller than the first size, each of the plurality of second closedcells being nested within a corresponding one of the plurality of firstclosed cells and coupled to the corresponding one of the plurality offirst closed cells at two attachment points, each of the plurality ofsecond closed cells sharing at least one strut with one of the pluralityof first closed cells, the frame further including a plurality ofcommissure features; and a valve assembly including a plurality ofleaflets and a cover.
 21. The prosthetic valve of claim 20, wherein theplurality of leaflets are coupled to the frame at the plurality ofcommissure features.